As is well known, an imaging device for implementing a color image includes color filters formed on a photosensitive portion for receiving light from the outside and generating and accumulating photocharges. The color filters may have colored patterns of three colors of red, green and blue, or may have colored patterns of three colors of yellow, magenta and cyan.
The colored pattern of each of the color filters is formed using a colored photosensitive resin composition including a pigment or a dye. The colored pattern formed of the colored photosensitive resin composition is generally prepared by lithography. In general, g-line (wavelength 436 nm) and i-line (wavelength 365 nm) are generally used in a light source for lithography used in preparing the color pattern.
In recent years, in order to achieve a high-pixel trend and improve picture quality, there has been demand for solid state imaging device having a pixel size reduced from 4-5 μm to 2 μm or less, such as a digital camera. Accordingly, micro-patterning and rectangular shapes of colored patterns are required.
To address the above demand, there has been research into techniques for forming a colored pattern using a colored photosensitive resin composition including dyes or forming a colored pattern by applying a dye to a prefabricated pattern. However, since the dye is poor in heat resistance and lightfastness, reliability of the dye may deteriorate. In addition, a pattern size, which can be implemented in a wavelength range of 365 nm to 463 nm, which is used for the light source used in the conventional process for color pattern formation, has reached a limit resolution.
Accordingly, the inventors of the present invention conducted research into technique for micro-patterning colored patterns of a color filter for a solid state imaging device using an ultra-short wavelength exposure device of 300 m or less. However, the conventional colored photosensitive resin composition is problematic in that hardening is not efficiently performed in ultra-short wavelength of 300 nm or less. In addition, even if hardening is performed in ultra-short wavelength of 300 nm or less, the sensitivity and resolution may deteriorate.